1. Field of the Invention
The invention relates to a gear housing in general and to a gear housing for an epicyclic gear set, in particular. The gear housing has a hollow wheel and a housing cover for longitudinally axially covering the hollow wheel. The invention further relates to a method for producing such a gear housing.
2. Background of the Invention
From EP 2 644 309 B1 is known a gear housing having a hollow wheel and a housing cover. The hollow wheel has internal teething in sections and is covered longitudinally axially by the housing cover. Between the housing cover and the hollow wheel, an overlap region is formed, in which the hollow wheel and the housing cover mesh coaxially. The hollow wheel features a material transparent to laser light so that the housing cover can be connected to the hollow wheel by means of laser transmission welding.
The known connection between the hollow wheel and the housing cover necessarily requires the use of a material transparent to laser light for the hollow wheel. It is, at the same time, required that the housing cover feature a laser light-absorbing material. The two materials that can be influenced by laser light in different ways must be adapted to each other such that they can be welded together. The two materials must, in particular, have differing laser light properties, but similar melting temperatures, in order to allow welding.
This significantly limits the selection of material for the components of the gear housing. It is, moreover, required that the housing cover and the hollow wheel be connected by a press fit prior to the welding process, so that sufficient contact exists between the joining surfaces. Such a press fitting process is difficult to realize, especially, in components produced by injection molding, and thus increases production costs. The production costs are also negatively influenced by the requirement of a laser light system, which creates high investment costs, for laser transmission welding. Additional effort of a technical nature arises in laser transmission welding when round gear housings must be welded, because the joining partners must rotate in the process.